Events are configurable

This commit mostly reproduces the structure of gestioncof's events,
renames some stuff and adds a generic export view.

events/models.py

@@ -16,7 +16,9 @@ class Event(models.Model):
     )
     registration_open = models.BooleanField(_("inscriptions ouvertes"), default=True)
     old = models.BooleanField(_("archiver (événement fini)"), default=False)
-    subscribers = models.ManyToManyField(User, verbose_name=_("inscrit⋅e⋅s"))
+    subscribers = models.ManyToManyField(
+        User, through="Registration", verbose_name=_("inscrit⋅e⋅s")
+    )
 
     class Meta:
         verbose_name = _("événement")
@@ -26,8 +28,91 @@ class Event(models.Model):
         return self.title
 
 
-# TODO: gérer les options (EventOption & EventOptionChoice de gestioncof)
-#       par exemple: "option végé au Mega (oui / non)"
+class Option(models.Model):
+    """Event options to be selected by participants at registration.
 
-# TODO: gérer les champs commentaires (EventCommentField & EventCommentChoice)
-#       par exemple: "champ "allergies / régime particulier" au Mega
+    The possible choices are instances of `OptionChoice` (see below). A typical example
+    is when the participants have the choice between different meal types (e.g. vegan /
+    vegetarian / no pork / with meat). In this case, the "meal type" is an `Option` and
+    the three alternatives are `OptionChoice`s.
+    """
+
+    event = models.ForeignKey(Event, on_delete=models.CASCADE, related_name="options")
+    name = models.CharField(_("option d'événement"), max_length=200)
+    multi_choices = models.BooleanField(_("choix multiples"), default=False)
+
+    class Meta:
+        verbose_name = _("option d'événement")
+        verbose_name_plural = _("options d'événement")
+
+    def __str__(self):
+        return self.name
+
+
+class OptionChoice(models.Model):
+    """A possible choice for an event option (see Option)."""
+
+    option = models.ForeignKey(Option, on_delete=models.CASCADE, related_name="choices")
+    choice = models.CharField(_("choix"), max_length=200)
+
+    class Meta:
+        verbose_name = _("choix d'option d'événement")
+        verbose_name_plural = _("choix d'option d'événement")
+
+    def __str__(self):
+        return self.choice
+
+
+class ExtraField(models.Model):
+    """Extra event field, for event creators.
+
+    Extra text field that can be added by event creators to the event registration form.
+    Typical examples are "remarks" fields (of type LONGTEXT) or more specific questions
+    such as "emergency contact".
+    """
+
+    LONGTEXT = "longtext"
+    SHORTTEXT = "shorttext"
+
+    FIELD_TYPE = [
+        (SHORTTEXT, _("texte court (une ligne)")),
+        (LONGTEXT, _("texte long (plusieurs lignes)")),
+    ]
+
+    event = models.ForeignKey(
+        Event, on_delete=models.CASCADE, related_name="extra_fields"
+    )
+    name = models.CharField(_("champ d'événement supplémentaire"), max_length=200)
+    field_type = models.CharField(_("type de champ"), max_length=9, choices=FIELD_TYPE)
+
+
+class ExtraFieldContent(models.Model):
+    field = models.ForeignKey(ExtraField, on_delete=models.CASCADE)
+    registration = models.ForeignKey(
+        "Registration", on_delete=models.CASCADE, related_name="extra_info"
+    )
+    content = models.TextField(_("contenu du champ"))
+
+    class Meta:
+        verbose_name = _("contenu d'un champ événement supplémentaire")
+        verbose_name_plural = _("contenus d'un champ événement supplémentaire")
+
+    def __str__(self):
+        max_length = 50
+        if len(self.content) > max_length:
+            return self.content[: max_length - 1] + "…"
+        else:
+            return self.content
+
+
+class Registration(models.Model):
+    event = models.ForeignKey(Event, on_delete=models.CASCADE)
+    user = models.ForeignKey(User, on_delete=models.CASCADE)
+    options_choices = models.ManyToManyField(OptionChoice)
+
+    class Meta:
+        verbose_name = _("inscription à un événement")
+        verbose_name_plural = _("inscriptions à un événement")
+
+    def __str__(self):
+        return "inscription de {} à {}".format(self.user, self.event)